Flying boat



T. B. SLATE May 14, 1946.

FLYING BOAT .2 Sheets-Sheet l awe/MM I'nowuaiiiB-Slnk Filed Oct. 23, 1941 May 14, 1946. T, BSLAT; I v 2,400,113

FLYING BOAT Filed Oct. 23, 1941 2 Sheets-Sheet 2 Patented May 14, 1946 UNITED STATES PATENT OFFICE FLYING BOAT Thomas B. Slate, Washington, D. ilpplica-tioncoctober 23, 1941, Serial No. 416,248 ,3 Claims. (01. 244- 106) The object of my invention is to provide a novel hydroplane mounted on the tail of flying boats to function as a control element and brake to enable the flying boat to safely alight on the water at high speed, and to more safely and at higher speed take off from the water. It is also my object to provide means for manually controlling this hydroplane; or alternatively, to arrange it for automatic operation.

I attain these and other objects of my invention by the mechanism illustrated in the accompanying drawings, in which- Figure -1 is a side elevation of the flying boat taxiing out for take on or taxiing in from landing, with the hydroplane in neutral position, parallel with the bottom of the flying boat;

Fig. 2 is aside elevation of the flying boa-t contacting the water for landing, with the hydroplane set in severe braking position as it enters the water;

Fig. 3 is a side elevation of the flying boat immediately after making contact with the water, showing the hydroplane pulling down heavily on the rear end of the boat and holding the front end clear of the water due to the resistance of the. keel cutting the water to permit the stern to submerge;

Fig. 4 is a detail view of a modification of the hydroplane arranged for automatic operation; and

Fig. 5 is a detail perspective view of the hydroplane alone.

Figs. 6 and '7 are detail views of the hydroplane.

Referring to the accompanying drawings, there is illustrated a hydroplane l of preferably approximately heart-shape, or with a pointed nose 2, having laterally expanding side or edge portions 3, and a downwardly slanting tail 4 extending rearwardly from the rear central portion of the hydroplane, as shown in Figs. 4, 6 and 7. The hydroplane l is pivotally mounted at 5 to the lowermost rear portion 6 of the tail of the flying boat I. The hydroplane preferably has an upstanding arm 8, to which an element 9 is attached at the upper end of the arm, the other end of the cable being connected to a manually operated lever I in the cockpit H of the flying boat. The flying boat I is provided with a suitablepropeller l2, engine 13, conventional or other wings I, ailerons l and conventional rudder I 6.

The operation of the hydroplane is illustrated in Figs. 1-3 of the drawings. The hydroplane is moved to severe braking position, as illustrated in Fig. 2, as the tail of the flying boat enters the water, and as shown in Fig. 3, it pulls down heavily on the rear end of the boat and holds the front end clear of the water due to the resistance of the keel cutting the water to permit the stern to submerge. The angularity of the boat to the surface of the water will gradually decrease as the speed decreases, allowing the main body of the boat to settle into the water gently. The severity of the angle of the hydroplane I to the surface of the water determines the time of the deceleration or stopping of the flying boat. That will be made more severe when the distance of clear water in front of the landing is short, and less severe when there is plenty of room. The angularity of the wings to the lines of the boat are such that the stern of the boat is lower than any other part during ordinary flight, and much lower when the angularity or angle of attack of the wings is correct for slowest speed flight; that is, with the point 2 of the hydroplane tilted downwardly to its greatest extent, as in Fig. 2.

In taking off, the hydroplane is set in a neutral position; or if in rough water, with a slight downdraft to prevent the flying boat from taking off or actually clearing the water until the pilot is ready, or so desires. Then the plane is thrown to a lifting position, throwing the stern clear of the water and releasing the drag due to the down-draft, to allow the flying boat to speed quickly into aerial night.

The importance of this landing device from a safety angle is due to the fact that regardless of the speed of the plane when it touches the water, it will adhere definitely to the surface of the water and not allow the flying boat to nose over into danger of crushing against waves or against the water itself from the nose or from the front. And having a natural balance of stem down, even if a very severe landing was made in a nose down or gliding position, contact from the nose would immediately throw the stern down, contacting the surface of the water and'p'ositively prevent the front end from being thrown up into a severe angle of attack and heavy resistance, causing the plane to lift quickly from the water, lose speed. and fall flat, as is so common in present practice.

Flying boats of conventional design have a very flat V-bottom, with a step amidships. From the step backward the tail of the conventional seaplane extends upward at a considerable angle to prevent it from touching the'water. The angle upward of the rear end of the conventional flying boa-t results in a down-draft'against the lift of the wings. When this type of boat lands, nose down, the heavy shock delivered to the front end causes it to rise quickly, giving the wings a sudden increase in lifting power, and causing the plane to lose speed rapidly both from the shock of striking the water and from the heavy resistance of the wings in a heavy angle of attack to the air. This rapid deceleration of the speed of the seaplane causes it to pancake down, or fall flat, and burst the bottom out of the boat. If it should land a little too much tail down it will nose right. over. into the water and smash from the frontend. Either occurrence is fatal to the boat and usually to its occupants. My hydroplane is designed to prevent such accidents.

The importance of safe higher landing speed is easily explained in view of the fact that a wing lifts according to the square of its speed. For example, a seaplane having 300 square feet of lifting surface will lift 2,312% pounds at 50 miles per hour; 9,250 pounds at 100 miles per hour; or 37,000 pounds at 200 miles per hour. Since the present take off and landing speed of high speed planes is about 100 miles per hour, any means of increasing this landing speed or take off speed to 200 miles per hour will increase the gross lifting capacity of the same seaplane 400 per cent. Since this increase comes to a plane of' the same size, making it only necessary to increase the power to carry the heavier load, the pay load capacity or useful load capacity may be increased as much as 600 or 700 per cent. However it is not contemplated that this means of landing should increase the landing speed only to 200 miles per hour. There is nothing indicated in the fundamental principles that would prevent landing speeds of 300 miles per hour, or more. It is reasonable practice for planes to have a cruising speed of more than'twice their landing speed.

The relative lift of wing area used in the above calculationis taken from N. A. C. A. records of a Clark Y-wing section, having a' coefficient of lift at maximum lift over drag (L over D) of .47; and a minimum or landing speed coefficient of lift of 1.2; or an L over D of approximately 22 at cruising speed and 12 at landing speed.

Referring to Fig. 4, illustrating the hydroplane without means for manual control, this modification shows the landing device for automatic control. Owing to the balance of the weight of the hydroplane la over the pivot 5, it will normally maintain a slight lifting angle of the hydroplane. Since the center of lift of any plane is near the front of the plane, any such lift helps to maintain that position, but when coming in contact with the water theltailpiece 4 strikes the water first and the resistance of the water being much greater than the air control of the plane, causes it to tilt to the severe landing position. that is, with the nose down. In installations of this kind it is contemplated that limits of severity of landingposition may be controlled from the pilot house, still leaving the ship control from neutral to landing position automatic.

I claim:

1. In combination with a flying boat, a hydroplane freely pivoted on the bottom of the stern of the boat, said hydroplane having a rearwardly extending tail disposed and balanced to first strike the water, and thereby tilt the hydroplane so that it will enter the Water'at an angle and function as a brake.

2. In combination with a flying boat, a hydro--v plane freely pivoted on the lower portion of the stern of the boat, said hydroplane having a rear- Wardly-extending downwardly-curved tail positioned and balanced so as to first strike the water and thereby tilt the hydroplane so that it will enter the water at an angle and function as a brake. f

3. In combination with the mechanism defined in claim I, manually controlled means operable from the cabin and operatively connected with the hydroplane for manually controlling its angle when entering or leaving the water, whereby to control the angle of the flying boat in taking oif from the water.

THOMAS B. SLATE.

landing or 

